Explosive



Patented Get. H, 1932 STTE GLENN ALBERT PRITCHETT, OF RENO, NEVADA.

EXPLOSIVE Application filed January 29, 1932. Serial No. 589,704.

My invention relates to explosives, and contemplates the production of aseries of explosive mixtures or compounds of mutually difierentcharacteristics and uses. all of which however possess in common certainnovel features and properties. The invention also contemplates a novelmethod of compounding explosives.

Principal objects of the invention are to provide a superior andinexpensive explosive product which will be free from certain seriousdisadvantages of explosives of the prior art hereinafter brieflyindicated.

The invention includes the use of dinitrotoluene of approximately afreezing point which has not been used in the manufacture of explosivesprior to my present invention. The novelty of my invention also residesprincipally in the elimination of certain ingredients heretoforeregarded as necessary to the production of explosives of comparablegrade. and in certain novel features of the processing of theingredients. all of which will hereinafter be more particularlydescribed and claimed.

The invention contemplates several varying formulae. each formulaproviding an explosive of differentgrade and influence. Dinitrotolueneis used in each formula. Th s material is commercially obtainable invarious grades characterized b difi'erentfreezing points ranging fromabout C. to 65 C. I have found it necessary to use DYT having a freezingpoint not lower than C. in order that the material may exist in acrystalline condition in the product.

The lowest grade explosive contemnlated by mv invention contains thefollowing ingredients:

Formula A Per cent Dmitrotoluene 10 Sodium nitrate 90 The sodium nitrateis sized between 8 and 18 mesh and thus introduced into the compositionin relatively granular form. as distinguished from the pulverulent statein which this material has been used heretofore. The nitrate grains usedin Formula A are such as pass an 8 mesh sieve and are retained on an 18mesh sieve. Consequently, none of the grains are larger than S mesh andnone are smaller than 18 mesh. The curve on the accompanying raph,hereinafter referred to, indicates the average size. I consider theproper sizing of the nitrate important and conducive to the improvedefficiency of the resulting product.

The DXT is warmed to a temperature above its melting point, say C. foraverage material. and mixed with the nit-rate. The mixture is maintainedabove the melting temperature of the DXT during the mixing operation toprevent crystallization of the liquid until an intimate mixture isobtained.

Upon cooling. the D'ST adheres as an oily coating to the nitrate grains,protecting the nitrate from moisture. and minimizing friction. Eachgrain of the product is an independent explosive agent, combustion beingtransmitted from one grain to another when the mixture is set off. Therelatively coarse character of the granular product prevents theexplosive becoming dense and insensitive to the influence of detonatorswhen packed tightly in machine loaded cartridges or tamped in blastholes.

The explosive product is solid at ordinary atmospheric temperatures.Disintegration and separation of constituents cannot therefore occur,and the efficacy and safety of the productare not affected by ordinaryclimatic changes. The explosive composition is superior in strength toordinary black blasting powder and is comparable thereto in cost ofproduction and safety in handling.

My product is equal in all respects to prior art explosives includingrelatively expensive sodium chlorate, which it has heretofore beenthought' 'ne'cessary to use in an amount equal to atleast 25% of thetotal weight of all ingredients in order to produce complete combustionwhen even the best detonator is employed.

An important object of the invention 15 produce an explosive compoundwhich will not pack densely, and to this end DNT is selected having afreezing point directly related to the size of the nitrate grains. Thelarger the annexed drawing, which formsv part of this application forLetters Patent, there is plotted a curve showing the ratio of grain sizeto DNT freezing points between 8 and 50 mesh and 65 and 25 C. Thethickness of the curve indicates the amount of variation in the ratio ofgrain size and freezing point which may be practiced without materiallysacrificing the benefits obtained by strictly observing the idealratios. -Thus, it will be noted that the ratio of DNT freezing point andnitrate grain size given for Formula A by way of example may be more orless departed from, especially by using DNT of a higher freezing point,since the nitrate grains in Formula A are large enough to preventdensity of pack in the product. It may, however, be stated that withnitrate grains of the size prescribed for Formula A, the freezing pointof. the DNT should not be lower than 40 C. It is important that the DNTbe in the frozen state in the product, and the smaller the grains theless solidly frozen must be the DNT. Otherwise the product packs denselyand becomes relatively insensitive to the action of ordinary fuse capsor electric exploders.

\Vhen substantially the ratio prescribed is followed a satisfactory lowgrade explosive compound is produced which is slightly higher inpercentage of strength than ordinary black blasting powder, which willdetonate consistently with No. 6 fuse caps or electric exploders, andwhich possesses resistance to friction, fire and impact superior to anyother comparable explosive of which I am aware.

To provide a more quickly burning and stronger explosive, havingotherwise all the advantages of the physical property of Formula A, Ireplace some of the nitrates of the formula with other ingredients,including a. chlorate, as follows:

Formula B Per cent Dinitrotoluene 10 Sodium nitrate 73 Sodium chlorate15 Lime 5 pulp provides carbon and serves to absorb and retain anyexcess oil.

A still stronger explosive is provided by further increasing theproportion of chlorate, as follows:

Formula 6' Per cent Dinitrotoluene 11 Sodium nitrate 56. 5 Sodiumchlorate 30 Lime .5 Wood pulp 2 In Formula C I prefer to use smallersized nitrate grains e. g.. such as sieve between 10 and 20 mesh. Toillustrate the latitude permissible in the ratio of DNT freezing pointand nitrate grain size, it may be stated that with nitrate grains soslightly reduced in size compared with those of Formula A. the DXT maybe of the same freezing point as that prescribed for Formula A, since inFormula C the nitrate grains are still large enough to prevent densityof pack in tlie product.

A still stronger product is given by the following formulae:

Fm'mula D Percent Dmitrotoluene 10 Sodium nitrate 41 Sodium chlorate39.5 Lime .5 Wood pulp -Q. 8 Mononitrotoluene 1 v Formula)? PercentDinitrotoluene 10 Sodium nitrate 44 Sodium chlorate 39. Lime .5 Bagasse.flour 5 Mononitrotoluene 1 These two formulae produce productssubstantially equal in strength, Formula E being desirable where it isnecessary to consider oxygen balance in the product and a lower carboncontentis required. Bagasse flour has almost twice the absorbentqualities of wood pulp. so that a smaller quantity may be used.

In Formulae D and E the nitrate grains are sized at not larger than 20mesh. Such reduction in grain size necessitates usin DNT of a lowerfreezing point, to prevent ensity of pack, and to this end a smallproportion of mononitrotoluene is added to the DNT. The freezing pointof the mixture of the two toluenes in Formulae D and E should be nothigher than 37 C.

In each formula the moisture content is less than 1%.

It is to be understood that the five formula set out hereinabove are'ven merely by way of example of several em iments of the 1nvention. Itwill be understood of course that an indefinite number of other formulasare contemplated by the invention, when explosives of varying strengthsare desired, all ex emplifying the characteristic ratio of toluenefreezing pointand nitrate grain size; Furthermore. slight departuresfrom the proportions of ingredients. temperatures, and grain sizesspecifically set out in the specification and appended claims areconsidered within the spirit of the invention and within the scope ofthe claims.

I claim :7

1. An explosive including DNT and'sodium nitrate in which the DNT has afreez- 5 ing point not lower than 40 6., and the grains of nitrate aresized between Sand 18 mesh. and in which the DNT is carried as a coatingon the nitrate grains.

2. An explosive as claimed in claim 1,

20 which contains substantially 10 parts of DNT and 90 parts of sodiumnitrate.

S.- An explosive as claimed in claim 1 which contains substantially 10parts of BN1, 7 3 parts of sodium nitrate and 15 parts of sodiumchlorate.

4. An explosive as claimed in claim 1 which contains substantially 10parts of DNT, 41 parts of sodium nitrate and 39.5 parts of sodiumchlorate.

5. An explosive including DNT and sodium nitrate in which the freezingpoint of the DNT and the grain size of the sodium nitrate are related asfollows: for nitrate grain sizes above 50 mesh to approximately 14 meshthe freezing point of the DNT varies directly with the grain sizebetween substantially 25 C. and substantially 41 C., and for nitrategrain sizes above 14 mesh to approximately 8 mesh the freezing point ofthe DNT varies directly with the grain size between substantially 41 C.and substantially 65 C.

6. The method of compounding an explosive containing DNT and sodiumnitrate in- 45 cluding the step of admixing DNT and sodium nitratehaving the following relation: for nitrate grain sizes above mesh toapproximately 14' mesh the freezing point of the DST varies directlywith the grain size 59 between substantially 25 C. and substantially 41C. and for nitrate grain sizes above 14 mesh to approximately 8 mesh thefreez= ing point of the DNT varies directly with the grain size betweensubstantially 41 C. and substantially 65C.

In testimony whereof I aflix my signature.

GLENN ALBERT PBITCHETT.

